Device-to-Device
Communication as an
Underlay to LTE-Advanced
Networks
Doppler, K.; Rinne, M.; Wijting, C.; Ribeiro, C.; Hugl, K.;
IEEE Communication Magazine, Vol. 47, No. 12, December
2009
Speaker: Tsung-Han Chiang
Date: March 9, 2012
1
Introduction
The authors outline a solution for a D2D session setup
using dedicated signaling and automatic handover of
network routed traffic to D2D links between nearby
(proximity) devices.
2
Session Setup by SIP
3
D2D Session Setup by Detecting
D2D Traffic
The session setup requires the following steps:
1.
2.
3.
4.
5.
6.
A session is initiated by one of the UE units.
The gateway detects IP traffic originating from and destined to
UE in the same subnet and to be tunneled within the same
serving eNB or between eNBs serving neighboring cells.
If the traffic fulfills certain criteria (e.g., data rate), the gateway
earmarks the traffic as potential D2D traffic.
The eNB(s) request measurement from the UE to check if D2D
communication offers higher throughput
If both UE units are D2D capable and D2D Communication offers
higher throughput, the eNB(s) may set up a D2D bearer.
Even if the D2D connection setup is successful, the eNB(s) still
maintain the SAE bearer between the UE and the gateway for
cellular communications.
4
D2D Session Setup by Detecting
D2D Traffic
7.
8.
Furthermore, the eNB maintains the radio resource control for
both cellular and D2D communication.
The UE will send/receive packets to/from the IP address of the
peer UE using the D2D connection without the eNB or SAR
being involved in routing.
5
D2D Session Setup by Detecting
D2D Traffic
The decision to establish a D2D connection can be based
on a defined policy such as limiting the number of D2D
connections to keep the interference to the cellular
network below a tolerable level.
A handover from a D2D connection to a cellular
connection is initiated when the cellular connection
achieves higher throughput than the D2D or if one of the
policies for D2D connections is violated.
6
D2D Session Setup Using
Dedicated SAE Signaling
A session setup using dedicated SAE signaling avoids the
overhead from detecting D2D traffic on the fly from IP
packets.
The new address format of D2D SIP could simply be
username@realm.D2D_keyword.
7
D2D Session Setup Using
Dedicated SAE Signaling
The authors propose to
encapsulate the SIP invite
message in an NAS control
plan message.
8
Conclusion
Throughput vs. Interference



Orthogonal frequency
Power Control
Others
9